This is a very useful resource for displaying the effect of changing the constants in a quadratic equation. You can display up to eight graphs at once which is helpful and you can also choose to hide the equations. There are many ways this could be used, it would make a nice plenary to get the students sketching the graphs on mini-whiteboards before revealing them, or visa versa you might get them to guess the equation to see how close they can get. Thank you for sharing.